1. Field of the Invention
This invention pertains to the field of collecting process generated fume and/or waste particulate matter (e.g. slag) generated by a process used to surface treat, cut, gouge or join a workpiece by means of elevated temperature (e.g. electric arc).
In particular the air-carbon arc cutting and gouging process is used to prepare metals for subsequent finishing operations such as welding. In the air-carbon arc cutting and gouging process an electric arc is struck between an electrode and a workpiece to initiate melting of the workpiece under the arc. The molten metal produced by the arc is forcibly removed from the workpiece by a stream of high pressure air. The air-carbon arc cutting and gouging process generates a large amount of fume because of the thermochemical reactions and produces waste particulate material in the form of a metal containing slag. With the advent of tighter air pollution control restrictions ways have been sought to prevent the process generated fume and/or slag from being forced into the ambient environment and in particular the environment within which the user of the process has to function.
2. The Prior Art
Fume collectors have been known for some time and are widely available for use with conventional welding torches. These devices are associated with a welding torch wherein as the welding proceeds, dense volumes of fume are produced which are forcibly removed by creating a partial vacuum in a sleeve disposed near the nozzle of the torch. The fume is sucked away from the torch head through a conduit and disposed of in a safe manner as is well known in the air handling art.
Insofar as the air-carbon arc cutting and gouging process is concerned and any other process that would generate fume and/or slag U.S. Pat. No. 3,524,038 discloses a device for removing solid particulate matter from the vicinity of the arc. The device of the '038 patent has been available for some time as a hand held tool or a machine mounted tool that must be used in close proximity to an air-carbon arc cutting and gouging torch. While the device of the '038 patent will remove some process generated fume, it will not provide the type of atmosphere movement to comply with current air pollution requirements.
The literature shows that in Japan installations employing the Air-Carbon Arc Cutting and Gouging Process have utilized conventional cutting tables with a water bath to collect slag generated by the process. The Japanese have further combined the conventional water table with a acoustically lined hood to contain fume and to control the noise level of the process in the immediate environment of the process user. This type of apparatus is not readily portable and requires a fixed installation where the workpiece must be transported to the installation to be treated.